Emacs bindings documentation - emacs

I am writing some bindings to lambdas in my ~/.emacs and would like to have a description of what the function does appear when I do (for example) C-c ?. I tried to put a string immediately after lambda () but that still does nothing. How do I get something relevant to appear in the binding column?
Example that still functionally works but documentation doesn't:
(global-set-key (kbd "M-p") (lambda ()
"Moves the current line up by one"
(interactive)
(let ((col (current-column)))
(transpose-lines 1)
(forward-line -2)
(forward-char col))))

You should use defun to define your interactive function and bind to that.
(defun my-func ()
"Moves the current line up by one"
(interactive)
(let ((col (current-column)))
(transpose-lines 1)
(forward-line -2)
(forward-char col)))
(global-set-key (kbd "M-p") 'my-func)

Related

bind key to negative-argument + command in emacs

I am trying to bind to M-b a command preceded by a negative argument. I post my code.
working
(global-unset-key (kbd "M-f"))
(global-set-key (kbd "M-f") 'forward-whitespace)
not working
(global-unset-key (kbd "M-b"))
(global-set-key (kbd "M-b") (lambda () (interactive) (negative-argument(forward-whitespace))))
How can I make it working?
The specific issue you have is solved easily:
(global-set-key (kbd "M-b") (lambda () (interactive) (forward-whitespace -1)))
You might wonder if you can write a macro that would call an arbitrary command interactively with negative argument.
It is not really hard:
(defmacro call-with-negative-argument (command)
`(lambda ()
(interactive)
(prefix-command-preserve-state)
(setq prefix-arg '-)
(universal-argument--mode)
(call-interactively ,command)))
(global-set-key (kbd "...") (call-with-negative-argument forward-whitespace))
but, really, any compliant function would also work fine like this:
(defmacro call-with-negative-argument (command)
`(lambda ()
(interactive)
(,command -1)))

emacs ow can I helm-find with default directory pre-specified?

I use emacs for notes mainly. All my notes are in:
~/Dropbox/Uni/Notes
I want to tie a keyboard shortcut (e.g C-f12) to do a helm-find that always starts in the above dir irrelevant of the source buffer.
I have tried:
(global-set-key (kbd "C-<f2>") (lambda () (interactive) (helm-find "~/Dropbox/Uni/Notes/")))
But when I run it, it still prompts me for 'DefaultDirectory' which is usually the same as the current buffer.
?
[edit]
I made a hack-around:
(global-set-key (kbd "<C-f2>")
(lambda ()
(interactive)
(find-file "~/Dropbox/Uni/Notes/leo.org")
(helm-find nil)))
That opens a file and then when I do a helm-find, it's relative to leo.org's location. But a better solution would be preferred.
[edit]
Below solution works perfectly.
Here you go:
(defmacro helm-find-note (dir)
`(defun ,(intern (format "helm-find-note-%s" dir)) ()
(interactive)
(let ((default-directory ,dir))
(helm-find nil))))
(global-set-key (kbd "C-M-3") (helm-find-note "~/Downloads"))

wrong type argument commandp with a custom function in emacs

I know this type of question have been asked by many people,
but I have read many similar posts and still have no idea
what to do. So here is the elisp code in .emacs:
;; send line to python console
(require 'python-mode)
(defun py-execute-line-down ()
"execute python line and move cursor down"
(progn
(py-execute-line)
(evil-next-line)))
(add-hook 'python-mode-hook
(lambda () (define-key python-mode-map (kbd "C-c C-j") 'py-execute-line-down)))
I also tried to add (interactive) into the function, it didn't work.
Just to keep the record here, this seemed to do the trick, not sure if it's optimal though:
;; send line to python console
(require 'python-mode)
(defun py-execute-line-down ()
"execute python line and move cursor down"
(interactive)
(py-execute-line)
(evil-next-line 1))
(defun kaiyin-pykeys ()
"python mode custome keys"
(local-set-key (kbd "C-c j") 'py-execute-line-down)
)
(add-hook 'python-mode-hook 'kaiyin-pykeys)
Taking Dan's advice, I changed the above into:
;; send line to python console
(require 'python-mode)
(defun py-execute-line-down ()
"execute python line and move cursor down"
(interactive)
(py-execute-line)
(forward-line 1))
(define-key python-mode-map (kbd "C-c j") 'py-execute-line-down)

local keymap for emacs outline-minor-mode

I want to set the outline-minor-mode for init.el file and when TAB key is pressed on the lines starting with ; the function outline-toggle-children should be called in order to fold and expand the sub headings.
Below is the code for hook. But it does not work for the "TAB" key binding as expected.
(add-hook 'emacs-lisp-mode-hook
(lambda ()
(if (equal (buffer-name) "init.el")
(progn
(outline-regexp "^;+")
(outline-minor-mode 1)
(local-set-key (kbd "TAB") ; this does not work
(lambda ()
(if (string-match outline-regexp (thing-at-point 'line))
(outline-toggle-children))))))))
I presume that the error you get is wrong-type-argument commandp. This happens because functions bound to keys must be "interactive" functions. You need to add an (interactive) declaration to the function, so that Emacs knows how to invoke the function in response to an event:
(lambda ()
(interactive)
(if (string-match outline-regexp (thing-at-point 'line))
(outline-toggle-children)))

.emacs global-set-key and calling interactive function with argument

In my .emacs i have the following function that transposes a line
(defun move-line (n)
"Move the current line up or down by N lines."
(interactive "p")
(let ((col (current-column))
start
end)
(beginning-of-line)
(setq start (point))
(end-of-line)
(forward-char)
(setq end (point))
(let ((line-text (delete-and-extract-region start end)))
(forward-line n)
(insert line-text)
;; restore point to original column in moved line
(forward-line -1)
(forward-char col))))
And I bind a key to it like this
(global-set-key (kbd "M-<down>") 'move-line)
;; this is the same as M-x global-set-key <return>
However, I want to bind M-up to move-line (-1) But I cant seem to be able to do it correctly:
;; M-- M-1 M-x global-set-key <return>
How do I define the above using global-set-key to call move-line -1?
Not minutes after asking the question I figured it out by copy+pasting code. However I have no clue how it works.
(global-set-key (kbd "M-<up>") (lambda () (interactive) (move-line -1)))
global-set-key only takes 2 arguments: the key sequence and the command you want to bind to it. So
(global-set-key (kbd "M-<down>") 'move-line)
works fine. But if you want to use move-line with an argument you need to wrap it in an anonymous (aka lamba) function so that it presents itself to global-set-key as one value.
You can simply ask for the number of lines you want and convert the input string into an integer:
(global-set-key (kbd "M-<up>")
(lambda ()
(interactive)
(move-line (string-to-int (read-string "Lines: ")))))
I found this when I had the same problem, but I ended up solving it in another way.
(global-set-key (kbd "M-<down>") 'move-line)
(global-set-key (kbd "M-<up>") (kbd "C-u -1 M-<down>"))
Definitely not a perfect solution, since M-<down> could be reassigned and C-u -1 might not make sense on it, but since it's just my local init file, it should be no problem.
Also this obvious only works well for keyboard commands that you want to have reversed.
You might want to check out the "transpose-lines" built-in function.